Variability in the edible fraction content of Co-60, Tc-99, Ag-110, Cs-137and Am-241 between individual crabs and lobsters from Sellafield (north eastern Irish Sea)

We investigated the variability in anthropogenic radionuclide content of th e edible fractions of individual edible crabs (Cancer pagurus L.) and Europ ean lobsters (Homarus gammarus L.) caught commercially in the Sellafield of fshore area. Sixteen female and 18 male crabs and 20 female and 17 male lob sters were selected from commercial catches made between 25 May and 5 June 1997. Each gender group was selected to be within the known weight range fo r commercially caught crustacea from the area. Four artificial radionuclide s (Co-60, Ag-110m, Cs-137 or Am-241) were detected by gamma -spectrometry. The edible fraction content of these radionuclides between males and female s for either species were not statistically significantly different. Tc-99 was analysed by chemical separation and beta -counting. Tc-99 concentration s in female crabs tended to be higher (172 +/- 205 (16) Bq kg (-1)(wet); me an +/- standard deviation (n samples)) than those in males (85 +/- 58 (18) Bq kg(-1) (wet)), although this was not a statistically significant differe nce. For both male and female crabs, Tc-99 concentrations tended to decreas e with increasing whole live weights. For Tc-99 in lobsters the picture is less clear. Female lobsters contained more activity (14800 +/- 7400 (20) Bq kg (-1) (wet)) than males (7100 +/- 3900 (17) Bq kg (-1) (wet)). The resul ts were used to discuss the implications for sampling and monitoring. Crown Copyright (C) 2001 Published by Elsevier Science Ltd. All rights reserved.